Hydrocarbon waxes have been used in rubber compositions to improve certain properties of the composition. In applications such as tires, wax has been used as an antiozonant. Chemical attack by ozone is thought to be one of the main causes of aging and deterioration of tires Effective waxes protect the rubber from ozone attack by migrating to the surface and forming a protective film on the tire. Waxes are also not typically thought of as improving the performance characteristics of the tire, such as traction or wear resistance.
Rubber compositions traditionally are made with aromatic processing oil, which enables the rubber compositions to be softened and more easily processed. Aromatic oil used in tire tread compositions can provide the tread rubber with improved traction over a composition with no oil. However, some European countries have passed regulations to limit the amount of aromatic oil or polycyclic-aromatic containing oil used in the rubber compositions. Many cost-effective substitutes for aromatic oil, such as synthetic ester oils and hydrogenated aromatic oils, do not provide the same beneficial properties imparted by traditional aromatic oils.